Threedimensional reconstruction of substantia nigra pars compacta of human brain

Background. Up to the moment there is no universally accepted scheme of spatial organization of the groups of neurons of substantia nigra pars compacta of the human midbrain. A detailed study of the architectonics of this structure is necessary for pathomorphological analysis of agerelated changes in the nervous tissue and the associated neurodegenerative diseases with selective death of dopamine neurons. Aim. To clarify the peculiarities of the morphochemical organization of the substantia nigra (SN) of a human brain and to create a threedimensional model of pars compacta. Materials and Methods. Threedimensional reconstruction of substantia nigra pars compacta was performed on the brain autopsy material of individuals without neurological pathology (n=10, between 52 to 84 years of age) using a method of computed morphometry. Sections of the midbrain were stained by Nissl method and by an immunohistochemical method for localization of tyrosine hydroxylase – a marker of dopamine. Results. In the SN pars compacta accumulations of neurons were identified in the form of 9 bands oriented in the rostrocaudal direction and including four areas: medial, lateral, dorsal and ventral. Morphometric analysis detected significant differences in the density of neurons and in expression of tyrosine hydroxylase between the areas of SN. Conclusion. A model of cellular organization of SN pars compacta proposed by us on the basis of threedimensional reconstruction is characterized by a high degree of detalization as compared to similar works, and shows expressed spatial differentiation of the groups of neurons of SN which should be taken into consideration in pathomorphological examinations.